diff mbox series

[SRU,J,2/7] arm64: kdump: Reimplement crashkernel=X

Message ID 20230710125612.37735-3-ioanna-maria.alifieraki@canonical.com
State New
Headers show
Series kdump fails on arm64 when offset is not specified | expand

Commit Message

Ioanna Alifieraki July 10, 2023, 12:56 p.m. UTC 
From: Chen Zhou <chenzhou10@huawei.com>

BugLink: https://bugs.launchpad.net/bugs/2024479

There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel in DMA zone, which
will fail when there is not enough low memory.
2. If reserving crashkernel above DMA zone, in this case, crash dump
kernel will fail to boot because there is no low memory available
for allocation.

To solve these issues, introduce crashkernel=X,[high,low].
The "crashkernel=X,high" is used to select a region above DMA zone, and
the "crashkernel=Y,low" is used to allocate specified size low memory.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20220506114402.365-4-thunder.leizhen@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(backported from commit 944a45abfabc171fd121315ff0d5e62b11cb5d6f)
[Changed memblock_phys_free() to memblock_free() because the first is
not present in this kernel.]
Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki@canonical.com>
---
 arch/arm64/kernel/machine_kexec.c      |  9 +++-
 arch/arm64/kernel/machine_kexec_file.c | 12 ++++-
 arch/arm64/mm/init.c                   | 63 +++++++++++++++++++++++---
 3 files changed, 74 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 213d56c14f60..6ea4dd1a6517 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -320,8 +320,13 @@  bool crash_is_nosave(unsigned long pfn)
 
 	/* in reserved memory? */
 	addr = __pfn_to_phys(pfn);
-	if ((addr < crashk_res.start) || (crashk_res.end < addr))
-		return false;
+	if ((addr < crashk_res.start) || (crashk_res.end < addr)) {
+		if (!crashk_low_res.end)
+			return false;
+
+		if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr))
+			return false;
+	}
 
 	if (!kexec_crash_image)
 		return true;
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 59c648d51848..889951291cc0 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -65,10 +65,18 @@  static int prepare_elf_headers(void **addr, unsigned long *sz)
 
 	/* Exclude crashkernel region */
 	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+	if (ret)
+		goto out;
+
+	if (crashk_low_res.end) {
+		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+		if (ret)
+			goto out;
+	}
 
-	if (!ret)
-		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);
+	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
 
+out:
 	kfree(cmem);
 	return ret;
 }
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 8c3ffcfc3b58..9fd61dfd9289 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -90,6 +90,32 @@  phys_addr_t __ro_after_init arm64_dma_phys_limit;
 phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
 #endif
 
+/* Current arm64 boot protocol requires 2MB alignment */
+#define CRASH_ALIGN			SZ_2M
+
+#define CRASH_ADDR_LOW_MAX		arm64_dma_phys_limit
+#define CRASH_ADDR_HIGH_MAX		(PHYS_MASK + 1)
+
+static int __init reserve_crashkernel_low(unsigned long long low_size)
+{
+	unsigned long long low_base;
+
+	low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
+	if (!low_base) {
+		pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
+		return -ENOMEM;
+	}
+
+	pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
+		low_base, low_base + low_size, low_size >> 20);
+
+	crashk_low_res.start = low_base;
+	crashk_low_res.end   = low_base + low_size - 1;
+	insert_resource(&iomem_resource, &crashk_low_res);
+
+	return 0;
+}
+
 /*
  * reserve_crashkernel() - reserves memory for crash kernel
  *
@@ -100,17 +126,35 @@  phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1;
 static void __init reserve_crashkernel(void)
 {
 	unsigned long long crash_base, crash_size;
-	unsigned long long crash_max = arm64_dma_phys_limit;
+	unsigned long long crash_low_size = 0;
+	unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
+	char *cmdline = boot_command_line;
 	int ret;
 
 	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
 		return;
 
-	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+	/* crashkernel=X[@offset] */
+	ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
 				&crash_size, &crash_base);
-	/* no crashkernel= or invalid value specified */
-	if (ret || !crash_size)
+	if (ret == -ENOENT) {
+		ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
+		if (ret || !crash_size)
+			return;
+
+		/*
+		 * crashkernel=Y,low can be specified or not, but invalid value
+		 * is not allowed.
+		 */
+		ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
+		if (ret && (ret != -ENOENT))
+			return;
+
+		crash_max = CRASH_ADDR_HIGH_MAX;
+	} else if (ret || !crash_size) {
+		/* The specified value is invalid */
 		return;
+	}
 
 	crash_size = PAGE_ALIGN(crash_size);
 
@@ -118,8 +162,7 @@  static void __init reserve_crashkernel(void)
 	if (crash_base)
 		crash_max = crash_base + crash_size;
 
-	/* Current arm64 boot protocol requires 2MB alignment */
-	crash_base = memblock_phys_alloc_range(crash_size, SZ_2M,
+	crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
 					       crash_base, crash_max);
 	if (!crash_base) {
 		pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
@@ -127,6 +170,11 @@  static void __init reserve_crashkernel(void)
 		return;
 	}
 
+	if (crash_low_size && reserve_crashkernel_low(crash_low_size)) {
+		memblock_free(crash_base, crash_size);
+		return;
+	}
+
 	pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
 		crash_base, crash_base + crash_size, crash_size >> 20);
 
@@ -135,6 +183,9 @@  static void __init reserve_crashkernel(void)
 	 * map. Inform kmemleak so that it won't try to access it.
 	 */
 	kmemleak_ignore_phys(crash_base);
+	if (crashk_low_res.end)
+		kmemleak_ignore_phys(crashk_low_res.start);
+
 	crashk_res.start = crash_base;
 	crashk_res.end = crash_base + crash_size - 1;
 }